Question about adding to the flock

For some background I currently have 1 frizzle, 3 BO, and 2 Australorp. They are now a year old. I ordered them from Mcmurray and had them vaccinated for Mareks and Cocci. I would like to add some variety this spring. My options are:

McMurray-carries SS, SF, EE, and Barred Rocks. I can get the vaccination for Marecks and Cocci. I have to order 25 minimum and I only want about 10 more chicks.

or

Ideal- carries SS, SF, EE, and Barred Cochins. I can get the vaccinations for Marecks but not for Cocci. I would be able to pick them up in person so no minimum order.

I really want to go with Ideal but I'm not sure about the vaccination part. Since my original flock was vaccinated do all birds that I bring in have to be vaccinated? I'm not sure if there is a time limit to the vaccination. Anyone got any opinions? Thanks!

I have ordered chicks from Ideal twice. I didn't have them vaccinated either time because they don't reccomend it for small flocks. I fed medicated starter-grower feed to both groups of birds.
Its been 6 months since I started and no problems yet. Just my opinion.

I don't get the shots and feed the medicated feeds to start out and have not had a problem...as a matter of fact...I don't know anyone that gets the vaccinations and all do well. I can be totally wrong on this but most of those issues are for large breeders that don't have time to really observe the birds individually. My two cents...not that it is worth that!

All of my birds have come from Ideal. I do not get them vaccinated. I feed medicated starter/grower to my chicks and straight layer to my big girls. When the little girls start laying and if I have any starter/grower left, I mix it with the layer. I don't worry about it being medicated. The medication is sulfa based. Only a problem if you have alergies to sulfa. There is a thread on BYC about this.